Campaign spending effects in U.S. Senate elections: Evidence from the National Annenberg Election Survey

The National Annenberg Election Survey of 2000 offers a fresh perspective on central issues in the long-standing debate about impact of campaign spending by congressional challengers and incumbents. Examination of changes over time and across panel waves in knowledge and evaluations of Senate candidates and in consequent voting intentions strongly confirms the efficacy of challengers' expenditures. Challengers gained support over time in direct proportion to their level of spending. Incumbents adjusted their level of spending to that of their challengers, and their levels of familiarity and favorability increased over time, but to a degree unrelated to how much they spent. Their expenditures did not appear to offset the effects produced by challengers' spending.